Hit hard by the intestinal-flu bug, Brandon Rush tossed and turned all Tuesday night.

“I was waking up every hour on the dot throwing up – 4:24, 5:24. It was really like that the whole night,” Rush said after mustering enough energy to play 33 minutes in Kansas University’s lethargic 63-43 victory over Detroit Mercy on Thursday night at Allen Fieldhouse.

“I threw up yesterday the whole day,” Rush said of a woozy Wednesday, which included a trip to the Watkins Memorial Health Center where he received an IV and some medicine.

“I had a little trash can by the bed. I’d empty it every time I’d throw up, not like their coach. I wasn’t just sitting there throwing up in front of 16,300 people,” Rush added after his nine-point, five rebound outing.

Rush was referring to Detroit assistant coach Garland Mance, who doubled over on the visitors bench and threw up with his Titans down 26-18 early in the second half.

Play was stopped as Mance was attended to and finally led to the locker room.

“I’ve never seen anybody too lazy to get up and go to the trash can. It just caught him off guard, I guess,” Rush cracked.

It turns out a third participant was affected by the bug – KU freshman Darrell Arthur, who had six points in 21 minutes (he missed all three free-throw tries on a night KU hit just 11 of 20).

Arthur told Rush he felt light-headed all day.

“He’s a little sick, too. I think his mind wasn’t into it at all. You could tell in the first half,” Rush said. “I don’t think anybody’s mind was into it except Mario. He played the whole game.”

KU’s only offensive threat was Mario Chalmers, who scored 22 points off 7-of-12 shooting. The only Jayhawk to score in double figures, he hit four of eight threes and four of five free throws.

“Mario was terrific,” KU coach Bill Self said. “I thought Brandon showed a lot of courage the second half. He was sick as a dog. Brandon really took Cotton (Brandon, 20 points, 8-of-20 shooting) out of it the last seven or eight minutes of the game.”

Self put Rush on Cotton with 8:55 left and KU up, 41-37. The (11-2) Jayhawks outscored (3-9) Detroit, 22-6, the rest of the way.

“Cotton scored at will every time he touched the ball. He made me work a lot,” Rush said. “He came around so many screens. He is so quick with that left hand. I’ve not seen anybody as quick with the opposite hand.”

He’s quicker than Rush, who didn’t blame the flu – just a puzzling lack of motivation – for his off night.

“I don’t think my head was into it at all. I don’t know why,” he said. “Everybody was outside their own mind, not into the game. We had a great shootaround. Everything was going our way. But when we came to the game, nobody was into it except Mario.”

The Jayhawks were miserable offensively the first half in scoring seven points the final 11:17, including a stretch of not scoring on 13 straight possessions, missing eight straight shots and five straight free throws.

KU finally woke up after Jon Goode stuck a three with 8:55 remaining to cut the gap to four points.

Julian Wright, who needed five stitches at halftime to close a cut on his chin, scored his first bucket of the game at 8:41 and followed that with another hoop off a pass from Rush, giving KU a 45-37 lead at 8:01.

Sasha Kaun (six points in 23 minutes) hit two free throws at 7:03 and Russell Robinson a three at 6:11, capping a 9-0 surge that gave KU a 50-37 advantage.

KU led 52-43 following a vicious Chalmers slam at 3:03, then put the game away with an 11-0 run led by five points from Chalmers and four from Rush.

The Jayhawks weren’t giddy after the victory, but accepted it as a ‘W’ on an off night.

“Anytime you win, you have to be somewhat happy,” said point guard Robinson. “It was sloppy. You will have those. We got one out of the way.”

Self was dejected after a game in which KU’s offense disappeared the first half after opening leads of 16-3 and 19-5.

“I have learned over the course of time you shouldn’t apologize for winning by 20, but we didn’t play well,” he said. “From a coach’s perspective, there were a lot of good things that happened, even if it wasn’t artistic.”

For instance, KU held Detroit to 43 points off 30 percent shooting. The Titans hit just five of 21 threes.

“Fifty percent of our game was good today,” Self said. “We guarded well. We did a great job on their big kid (Ryvon Covile, seven points, 3-of-8 shooting with 10 rebounds). Sasha did a terrific job on him.”

The Jayhawks have one day to work on things before playing again. Rhode Island (7-6) will travel to Allen Fieldhouse Saturday for another 7 p.m. tipoff.